FAN POWER SUPPLY CONTROL SYSTEM

Abstract

A fan power supply control system includes a power supply module, a power control circuit, a signal control circuit, a PWM generator. The power supply is adapted to input a power signal to a fan. The power control circuit is between the power supply module and the fan and adapted to connect or disconnect the power supply module to the fan. The signal control circuit is connected the power supply module to the power control circuit and adapted to switch on or off the power control circuit. The PWM generator is adapted to generate a predetermined cycle square signal according to the power signal, to intermittently switch on or off the signal control circuit, and a switch on/off state of the power control circuit is synchronous with the signal control circuit.

Description

BACKGROUND

1. Technical Field

The present disclosure relates to a fan power supply control system.

2. Description of Related Art

A computer system sometimes includes a fan for dissipating heat generated by heat generation component, such as central processing unit (CPU). Usually, the fan is provided with a power supply circuit. The power supply circuit supplies power to the fan and includes a plurality of transistors. When the fan starts, the power supply circuit may generate a current spike and damage the plurality of transistors. Therefore, there is a need for improvement in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

FIG. 1 is a block view of an embodiment of a fan power supply control system.

FIG. 2 is a circuit view of the fan power supply control system of FIG. 1.

DETAILED DESCRIPTION

The disclosure is illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean “at least one.”

FIG. 1 shows one embodiment of a fan power supply circuit includes a power supply module 20, a filtering circuit 30, a power control circuit 50, a signal control circuit 60, a pulse width modulation (PWM) generator 70, and a charging and discharging circuit 80.

The power supply module 20 provides a power to a fan 90. In one embodiment, the power supply module 20 may input a power signal with a current spike, and the current spike has a predetermined time. The filtering circuit 30 is electrically coupled to the power supply module 20 and adapted to filter a power signal input by the power supply module 20. The signal control circuit 60 is electrically connected to the power control circuit 50 and the filtering circuit 30. The signal control circuit 60 is adapted to switch on or off the power control circuit 50. The PWM generator 70 is electrically connected to the signal control circuit 60 and adapted to control the signal control circuit 60 to be switched on or off. The charging and discharging circuit 80 is electrically coupled to the power control circuit 50 and the fan 90.

FIG. 2 shows that, the filtering circuit 30 includes a first capacitor C1 and configured to filter the power signal, the first capacitor C1 filtering a high frequency of the power signal, for example. A first end of the first capacitor C1 is electrically connected to a positive electrode of the power supply module 20, and a second end of the first capacitor C1 is electrically connected to a negative electrode of the power supply module 20 and is grounded.

The power control circuit 50 is adapted to connect or disconnect the power supply module 20 to the fan 90 and includes a first resistor R1, a second capacitor C2, and a first MOSFET Q1. The first resistor R1 and the second capacitor C2 are in parallel. A first end of the first resistor R1 is electrically connected to the positive electrode of the power supply module 20 and a first end of the second capacitor C2. A second end of the first resistor R1 is electrically connected to the second end of the second capacitor C2. A source electrode of the first MOSFET Q1 is electrically connected to the first ends of the first resistor R1 and the second capacitor C2. A grid electrode of the first MOSFET Q1 is electrically connected to the second end of the first resistor R1 and the signal control circuit 60. The drain electrode of the first MOSFET Q1 is electrically connected to the charging and discharging circuit 80.

The signal control circuit 60 is a second MOSFET Q2. A source electrode of the second MOSFET Q2 is grounded. A drain electrode of the second MOSFET Q2 is electrically connected to the grid electrode of the first MOSFET Q1. A grid electrode of the second MOSFET Q2 is electrically connected to a first end of a second resistor R2. A second end of the second resistor R2 is electrically connected to a working voltage VCC. The switching on/off of the power control circuit 50 is synchronous with the signal control circuit 60.

The PWM generator 70 is electrically connected to the first end of the second resistor R2 and adapted to generate a predetermined square signal according to the power signal switching the second MOSFET Q2 on or off

The charging and discharging circuit 80 includes a third resistor R3, a diode D1, a third capacitor C3, and a fourth capacitor C4. The third resistor D1, the diode D1, the third capacitor C3, and the fourth capacitor C4 are in parallel. A first end of the third resistor R3 is electrically connected to the drain electrode of the first MOSFET Q1 and the fan 90, and the second end of the third resistor R3 is grounded. A negative electrode is electrically connected to the drain electrode of the first MOSFET Q1 and the fan 90, and a positive electrode is grounded. A first end of the third capacitor C3 is electrically connected to the drain electrode of the first MOSFET Q1 and the fan 90, and a second end of the third capacitor C3 is grounded. A first end of the fourth capacitor C4 is electrically connected to the drain electrode of the first MOSFET Q1 and the fan 90, and a second end of the fourth capacitor C4 is grounded.

The power supply module 20 begins to work to provide the working voltage VCC, and the second MOSFET Q2 switches on. The first MOSFEET Q1 switches on, and the power module 20 charges the third capacitor C3, the fourth capacitor C4, and provides power to the fan 90. When the PWM generator 70 generates a low level signal to the second MOSFET Q2, the second MOSFET Q2 is switched off to switch off the first MOSFET Q1. At this time, the power supply module 20 may generate the current spike, thus, the first MOSFET Q1 does not get damaged. The third capacitor C3 and the fourth capacitor C4 discharge to the fan 90. When the PWM generator 70 generates a high level signal to the second MOSFET Q2, the second MOSFET Q2 is switched on to switch on the first MOSFET Q1. The power module 20 continually provides power to the fan 90. When a rotating speed of the fan 90 is stable, the predetermined cycle of PWM generator 70 ends. The second MOSFET Q2 continues to switch on under the working voltage VCC, to continually switch on the first MOSFET Q1. The fan 90 runs steadily.

Even though numerous characteristics and advantages of the present disclosure have been set forth in the foregoing description, together with details of the structure and function of the disclosure, the disclosure is illustrative only, and changes may be made in detail, especially in the matters of shape, size, and the arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.

Claims

1. A fan power supply control system comprising:

a power supply module adapted to input a power signal to a fan; and

a power control circuit being between the power supply module and the fan, and the power control circuit adapted to connect or disconnect the power supply module to the fan;

a signal control circuit connected the power supply module to the power control circuit, and the signal control circuit adapted to switch on or off the power control circuit; and

a pulse width modulation (PWM) generator adapted to generate a predetermined cycle square signal according to the power signal, to intermittently switch on or off the signal control circuit, and a switching on/off state of the power control circuit being synchronous with the signal control circuit.

2. The fan power supply control system of claim 1, further comprising a filtering circuit electrically connected to the power supply module and the power control circuit, wherein the filtering circuit is adapted to filter the power signal.

3. The fan power supply control system of claim 2, wherein the filtering circuit comprises a first capacitor, a first end of the first capacitor is electrically connected to a positive electrode of the power supply module, and a second end of the first capacitor is grounded.

4. The fan power supply control system of claim 1, wherein the power control circuit comprises a first resistor and a second capacitor, and the first resistor and the second capacitor are in parallel.

5. The fan power supply control system of claim 4, wherein the power control circuit further comprises a first MOSFET, and a source electrode of the first MOSFET is electrically coupled to a first end of the first resistor, a grid electrode of the first MOSFET is electrically connected to a second end of the first resistor and the signal control circuit, and the drain electrode of the first MOSFET is connected to fan.

6. The fan power supply control system of claim 5, wherein the signal control circuit is a second MOSFET, a drain electrode of the second MOSFET is electrically connected to the grid electrode of the second MOSFET, a grid electrode of the second MOSFET is electrically connected to a second resistor, and a source electrode of the second MOSFET is grounded.

7. The fan power supply control system of claim 6, wherein a first end of the second resistor is coupled to the PWM generator and the grid electrode of the second MOSFET, and the second end of the second resistor is connected to a work voltage.

8. The fan power supply control system of claim 5, further comprising a charging and discharging circuit connected to the first MOSFET and the fan, wherein the charging and discharging comprises a third resistor, a diode, a third capacitor, and the a fourth capacitor, and the third resistor, the diode, the third capacitor and the fourth capacitor are in parallel.

9. The fan power supply control system of claim 8, wherein a positive electrode of the diode is grounded, and the negative electrode of the diode is connected to the drain electrode of the first MOSFET.

10. The fan power supply control system of claim 6, wherein the power signal has a current spike, the PWM generator is adapted to generate a low level signal to switch off the second MOSFET when the power signal is in the current spike.

11. A fan power supply control system comprising:

a power supply module adapted to input a power signal to a fan; and

a power control circuit being between the power supply module and the fan;

a signal control circuit connected the power supply module to the power control circuit; and

a PWM generator adapted to generate a predetermined cycle square signal according to the power signal, to intermittently switch on or off the signal control circuit,

wherein the signal control circuit is switched on when the PWM generator generates a high level signal, and the power control circuit switches on to connect the power supply module to the fan; the signal is switched off when the PWM generator generates a low level signal, and the power control circuit is switched off to disconnect the power supply module from the fan.

12. The fan power supply control system of claim 11, further comprising a filtering circuit electrically connected to the power supply module and the power control circuit, wherein the filtering circuit is adapted to filter the power signal.

13. The fan power supply control system of claim 12, wherein the filtering circuit comprises a first capacitor, a first end of the first capacitor is electrically connected to a positive electrode of the power supply module, and a second end of the first capacitor is grounded.

14. The fan power supply control system of claim 11, wherein the power control circuit comprises a first resistor and a second capacitor, and the first resistor and the second capacitor are in parallel.

15. The fan power supply control system of claim 14, wherein the power control circuit further comprises a first MOSFET, and a source electrode of the first MOSFET is electrically coupled to a first end of the first resistor, a grid electrode of the first MOSFET is electrically connected to a second end of the first resistor and the signal control circuit, and the drain electrode of the first MOSFET is connected to fan.

16. The fan power supply control system of claim 15, wherein the signal control circuit is a second MOSFET, a drain electrode of the second MOSFET is electrically connected to the grid electrode of the second MOSFET, a grid electrode of the second MOSFET is electrically connected to a second resistor, and a source electrode of the second MOSFET is grounded.

17. The fan power supply control system of claim 16, wherein a first end of the second resistor is coupled to the PWM generator and the grid electrode of the second MOSFET, and the second end of the second resistor is connected to a work voltage.

18. The fan power supply control system of claim 15, further comprising a charging and discharging circuit connected to the first MOSFET and the fan, wherein the charging and discharging comprises a third resistor, a diode, a third capacitor, and the a fourth capacitor, and the third resistor, the diode, the third capacitor and the fourth capacitor are in parallel.

19. The fan power supply control system of claim 18, wherein a positive electrode of the diode is grounded, and the negative electrode of the diode is connected to the drain electrode of the first MOSFET.

20. The fan power supply control system of claim 16, wherein the power signal has a current spike, the PWM generator is adapted to generate a low level signal to switch off the second MOSFET when the power signal is in the current spike.